export function LocalFileDown(res, filename) {
  const content = res ;
  const blob = new Blob([content]) ;
  if ('download' in document.createElement('a')) { // 非IE下载
    const elink = document.createElement('a') ;
    elink.download = filename ;
    elink.style.display = 'none' ;
    elink.href = URL.createObjectURL(blob) ;
    document.body.appendChild(elink) ;
    elink.click() ;
    URL.revokeObjectURL(elink.href) ; // 释放URL 对象
    document.body.removeChild(elink) ;
  } else { // IE10+下载
    navigator.msSaveBlob(blob, fileName) ;
  }
}